employed its "Red Drover" sideways-looking radar to find targets for attack by the V bomber force that would follow. As development had progressed, it became clear that the radar would not necessitate as bulky an antenna as initially believed, which had the result of freeing up considerable internal space. In response, the RAF began to concentrate on a secondary bombing role for the type, for which it was to carry both the radar along with a long bomb bay, in which either a weapon or additional fuel could be contained within. A high-speed bomber requirement was also being studied at the time, OR.336, so the two projects were combined into the new RB.156 requirement in October 1955. This led to the Avro 730 undergoing a fairly substantial redesign to correspond with the new requirements being issued. Avro had anticipated this eventuality in their original submission. The envisioned test program was to have been quite thorough, which would have involved subjected full-scale aircraft to the severe temperatures anticipated at Mach 2.5 flight via a purpose-built heat chamber; upon reaching the flight testing phase, the prototypes had been scheduled to perform a total of 1,400 flight hours. The first prototype, which had received the internal designation Avro 731, a three-eighths scale aircraft for testing purposes, was scheduled to fly in 1959. A pair of Avro 731 prototypes were set to be built and flown in advance of the full-scale prototypes. The first prototype was under construction when the minister, Duncan Sandys, announced the decision to cancel its development in 1957. It had been suspected that by the time the aircraft came into service a decade later it would have been vulnerable to Soviet advances in anti-aircraft missile technology. Effort was instead transferred to the Blue Streak medium-range ballistic missile, while the sole 730 test fuselage was cut up. The Bristol 188 project continued despite the cancellation of the 730. Aspects and influences of the Avro 730 encouraged studies at the Royal Aircraft Establishment, Farnborough, into supersonic transport aircraft, which in turn eventually contributed to the development effort behind Concorde. Design The Avro 730 was a very high speed aircraft that was originally designed solely for aerial reconnaissance purposes. In order to achieve the desired high speed performance, the aircraft consisted of a long, slender fuselage with a high fineness ratio and a small, tapered, almost rectangular wing that was mounted centrally on